At the medical site, a medical imaging apparatus such as an X-ray CT apparatus, MRI apparatus, or PET apparatus captures a three-dimensional medical image formed from a plurality of tomographic images. When performing radiogram interpretation of these medical images and performing image diagnosis, a doctor displays (scrolls and displays) a plurality of tomographic images while successively switching them, observes the entire three-dimensional medical image, and finds out and evaluates an abnormal shadow in the image. To perform more accurate image diagnosis, a so-called MPR (Multi-Planar Reconstruction) method is sometimes used. According to this method, a three-dimensional medical image is reconstructed into an image (to be referred to as a tomographic image hereinafter) of a slice in an arbitrary direction (to be referred to as a tomographic direction hereinafter), and the reconstructed three-dimensional medical image is displayed. By using this method, tomographic images in a plurality of tomographic directions are created, displayed, and used for radiogram interpretation.
Recently, an increase in the number of images of medical images and complication of them are proceeding owing to an increase in the number of patients against the background of an aging society and an increase in the amount of information along with medical advance. Therefore, the burden on a doctor in radiogram interpretation operations is rapidly increasing, and there is a fear of an increase in misses or evaluation errors of abnormal shadows (to be referred to as radiogram interpretation omission hereinafter).
Japanese Patent Laid-Open No. 2007-319327 (to be referred to as literature 1 hereinafter) discloses a technique of recording the operation of a system and sight line information of a radiogram interpreter in time series at the time of radiogram interpretation. According to this technique, by measuring and recording the sight line of the radiogram interpreter to a radiogram interpretation target image, the radiogram interpreter can identify an observed region and an unobserved region, and can point out radiogram interpretation omission of the unobserved region.
However, in literature 1, an observed region and an unobserved region are merely identified on an image displayed by the system based on the operation record and sight line information of the system. For example, as a result of interpreting an image displayed in an improper display state, some organs and abnormal shadows may not be displayed clearly and may not be interpreted appropriately. In literature 1, even when such an improperly displayed image is observed, it is determined from sight line information that the region has been observed.